Method and system for rf interference mitigation using a blanking watchguard

ABSTRACT

A global navigation satellite system (GNSS) enabled mobile device may be operable to assert one of autoblank signals when RF interference is detected in received GNSS signals for one of consecutive first time windows. The asserted autoblank signals are monitored by the GNSS enabled mobile device over time intervals corresponding to consecutive second time windows and a rate at which the autoblank signals are asserted for each of the consecutive second time windows is determined by the GNSS enabled mobile device based on the monitoring. The GNSS enabled mobile device may be operable to determine whether to blank processing of the received GNSS signals based on the determined rate. The autoblank signals may be asserted by the GNSS enabled mobile device based on a number of the received GNSS signals whose absolute signal levels exceed a signal level threshold for the first time window.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

[Not applicable]

FIELD OF THE INVENTION

Certain embodiments of the invention relate to wireless communication.More specifically, certain embodiments of the invention relate to amethod and system for RF interference mitigation using a blankingwatchguard.

BACKGROUND OF THE INVENTION

The global positioning system (GPS), the global orbiting navigationsatellite system (GLONASS), and the satellite navigation system GALILEOare examples of global navigation satellite systems (GNSS). A GNSSutilizes an earth-orbiting constellation of a plurality of satelliteseach broadcasting GNSS signals which indicates its precise location andranging information. From particular locations on or near the earth,GNSS receivers may detect valid GNSS signals using a temperaturecompensated crystal oscillator (TCXO) and take various GNSS measurementssuch as pseudorange, carrier phase, and/or Doppler to calculatenavigation information such as GNSS receiver positions, velocity, andtime.

The GNSS receivers may be integrated within or externally coupled tomobile devices for exemplary navigation applications comprising E911,location-based 411, location-based messaging. The mobile devices mayprovide connections to access applications such as route tracking,multimedia communication, song downloading, instant messaging, makingphone call, and/or mobile television (TV). In mobile devices there maybe multiple sources of RF interference. Such interference may be presentin a GNSS band and may result from unintentional sources, such as TV/FMharmonics, radar, MSS, or may result from hostile (jamming) efforts.Some interference sources are continuous, such as WCDMA transmissions orspurious emissions from other circuits, while others are pulse (burst),such as GSM or EDGE transmissions.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with the present invention as set forth inthe remainder of the present application with reference to the drawings.

BRIEF SUMMARY OF THE INVENTION

A system and/or method for RF interference mitigation using a blankingwatchguard, substantially as shown in and/or described in connectionwith at least one of the figures, as set forth more completely in theclaims.

Various advantages, aspects and novel features of the present invention,as well as details of an illustrated embodiment thereof, will be morefully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating an exemplary communication system thatis operable to provide RF interference mitigation using a blankingwatchguard, in accordance with an embodiment of the invention.

FIG. 2 is a block diagram illustrating an exemplary GNSS enabled mobiledevice that is operable to provide RF interference mitigation using ablanking watchguard, in accordance with an embodiment of the invention.

FIG. 3 is a block diagram illustrating an exemplary GNSS receiver thatis operable to provide RF interference mitigation using a blankingwatchguard, in accordance with an embodiment of the invention.

FIG. 4 is a block diagram illustrating an exemplary GNSS autoblankerthat is operable to provide RF interference mitigation using a blankingwatchguard, in accordance with an embodiment of the invention.

FIG. 5 is a flow chart illustrating exemplary steps for RF interferencemitigation using autoblanking, in accordance with an embodiment of theinvention.

FIG. 6 is a flow chart illustrating exemplary steps for blankingwatchguard during RF interference mitigation process, in accordance withan embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention can be found in a method and systemfor RF interference mitigation using a blanking watchguard. In variousembodiments of the invention, a global navigation satellite system(GNSS) enabled mobile device may be operable to determine a rate atwhich autoblank signals are asserted. The autoblank signals may beasserted during the RF interference mitigation process usingautoblanking. The GNSS enabled mobile device may be operable to controlthe processing of received GNSS signals based on the determined rate ofasserted autoblank signals. In this regard, the GNSS enabled mobiledevice may be operable to monitor the autoblank signals over timeintervals corresponding to consecutive time windows. The GNSS enabledmobile device may be operable to determine a count of the autoblanksignals that are received during the time interval corresponding to thetime window. The GNSS enabled mobile device may be operable to comparethe determined count to a count threshold. In this regard, the count maybe, for example, a percentage of time within the time window when theautoblank signals are received, and the count threshold may be aparticular percentage of time. The count may also be, for example, atotal number of the autoblank signals received during the time window,and the count threshold may be a particular number of the autoblanksignals. The GNSS enabled mobile device may be operable to disable thegeneration of a blank signal when the count is greater than the countthreshold at the end of the time window. The GNSS enabled mobile devicemay be operable to enable the generation of a blank signal when thecount is less than or equal to the count threshold at the end of thetime window, and the blank signal is used to blank the processing ofreceived GNSS signals. The GNSS enabled mobile device may be operable todisable the generation of a blank signal when the count is greater thanthe count threshold at a time, for example, prior to the end of the timewindow. The GNSS enabled mobile device may be operable to enable thegeneration of a blank signal when the count is less than or equal to thecount threshold at a time, for example, prior to the end of the timewindow, and the blank signal is used to blank the processing of receivedGNSS signals.

FIG. 1 is a diagram illustrating an exemplary communication system thatis operable to provide RF interference mitigation using a blankingwatchguard, in accordance with an embodiment of the invention. Referringto FIG. 1, there is shown a communication system 100. The communicationsystem comprises a plurality of GNSS enabled mobile devices 110, ofwhich GNSS enabled mobile devices 110 a-110 d are illustrated, a GNSSinfrastructure 120, a wireless communication network 130. The GNSSinfrastructure 120 comprises a plurality of GNSS satellites such as GNSSsatellites 120 a through 120 c.

A GNSS enabled mobile device such as the GNSS enabled mobile device 110a may comprise suitable logic, circuitry, interfaces and/or code thatare operable to communicate radio signals across the wirelesscommunication network 130. The GNSS enabled mobile device 110 a may beoperable to receive GNSS broadcast signals from a plurality of visibleGNSS satellites such as GNSS satellites 120 a through 120 c in the GNSSinfrastructure 120. The received GNSS signals may be utilized todetermine navigation information such as a position fix and/or avelocity of the GNSS enabled mobile device 110 a. The determinednavigation information such as a position fix of the GNSS enabled mobiledevice 110 a may be communicated with, for example, the wirelesscommunication network 130, for various navigation applications such asE911, location-based 411, location-based messaging, etc.

The GNSS signals that are received by the GNSS enabled mobile device 110a may comprise RF interference. In some instances when the RFinterference level is high, the RF interference may almost wipe out theGNSS signal to the point where it may be better not to process the GNSSsignal (blank the GNSS signal processing) during that time using a RFinterference mitigation method, such as, for example, the autoblankingmethod. Some RF interference occurs continuously such as in WCDMAtransmissions (continuous jammer) in the wireless communication network130 and some RF interference occurs for a short burst of time such as inGSM or EDGE transmissions (burst jammer) in the wireless communicationnetwork 130. In instances when the RF interference is a continuousjammer, the autoblank signals asserted using autoblanking may not bestopped for a long time or may never be stopped during the RFinterference mitigation process. In this regard, the GNSS enabled mobiledevice 110 a may be operable to perform the RF interference mitigationusing autoblanking and blank monitoring with watchguard. During the RFinterference mitigation process, the GNSS enabled mobile device 110 amay be operable to assert autoblank signals using autoblanking. The GNSSenabled mobile device 110 a may be operable to monitor and determine therate of the autoblank signals and control the blanking of processing ofreceived GNSS signals based on the rate of the autoblank signals. Ininstances when it is determined that the rate of the autoblank signalsis too high, for example, the rate exceeds a particular rate threshold,the GNSS enabled mobile device 110 a may be operable to disable or stopthe blanking of processing of received GNSS signals.

A GNSS satellite such as the GNSS satellite 120 a may comprise suitablelogic, circuitry, interfaces and/or code that is operable to providesatellite navigational information to various GNSS receivers on earth.In an embodiment of the invention, the GNSS receivers, such as GPS,GALILEO or GLONASS receivers, may be integrated within GNSS capablemobile devices such as the GNSS enabled mobile devices 110 a through 110d.

The wireless communication network 130 may comprise suitable logic,circuitry, interfaces and/or code that may be operable to provide voiceand data services to various mobile devices such as the GNSS enabledmobile devices 110 a-110 d by using wireless communication technologiessuch as, for example, WCDMA, GSM, GPRS, UMTS, EDGE, EGPRS, LTE, WiMAX,WiFi, and/or Bluetooth.

In operation, a GNSS enabled mobile device such as the GNSS enabledmobile device 110 a may be operable to detect and receive GNSS signalsfrom, for example, the GNSS satellites 120 a-120 c. The GNSS enabledmobile device 110 a may be operable to perform the RF interferencemitigation using autoblanking and blank monitoring with watchguard.During the RF interference mitigation process, the GNSS enabled mobiledevice 110 a may be operable to assert autoblank signals usingautoblanking. The GNSS enabled mobile device 110 a may be operable tomonitor and determine the rate of the autoblank signals and control theblanking of processing of received GNSS signals based on the rate of theautoblank signals. In instances when it is determined that the rate ofautoblank signals is too high, for example, the rate exceeds aparticular rate threshold, the GNSS enabled mobile device 110 a may beoperable to disable or stop the blanking of processing of received GNSSsignals.

FIG. 2 is a block diagram illustrating an exemplary GNSS enabled mobiledevice that is operable to provide RF interference mitigation using ablanking watchguard, in accordance with an embodiment of the invention.Referring to FIG. 2, there is shown a GNSS enabled mobile device 200.The GNSS enabled mobile device 200 may comprise a GNSS receiver 202, awireless transceiver 204, a host processor 208, and a memory 210.

The GNSS receiver 202 may comprise suitable logic, circuitry, interfacesand/or code that may be operable to detect and receive GNSS signals froma plurality of visible GNSS satellites 120 a-120 c. The GNSS receiver202 may be operable to utilize the received GNSS signals to calculatenavigation information such as a position fix and/or velocity of theGNSS receiver 202. The calculated navigation information may be providedto the host processor 208 to be communicated with the wirelesscommunication network 130 for various navigation applications such as,for example, location-based 411. The GNSS receiver 202 may be operableto perform RF interference mitigation using autoblanking and blankmonitoring with watchguard. During the RF interference mitigationprocess, the GNSS receiver 202 may be operable to assert autoblanksignals using autoblanking. The GNSS receiver 202 may be operable tomonitor and determine the rate of the autoblank signals and control theblanking of processing of received GNSS signals based on the rate of theautoblank signals. In instances when it is determined that the rate ofautoblank signals is too high, for example, the rate exceeds aparticular rate threshold, the GNSS receiver 202 may be operable todisable or stop the blanking of processing of received GNSS signals.

The wireless transceiver 204 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to communicate radio signalsover the wireless communication network 130.

The host processor 208 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to process signals from theGNSS receiver 202 and the wireless transceiver 204. The host processor208 may be operable to communicate signals with the wirelesscommunication network 130 via the wireless transceiver 204. The hostprocessor 208 may be operable to communicate navigation information withthe wireless communication network 130 for various navigationapplications such as location-based 411 and/or roadside assistance.

The memory 210 may comprise suitable logic, circuitry, and/or code thatoperable to store information such as executable instructions and datathat may be utilized by the host processor 208. The memory 210 maycomprise RAM, ROM, low latency nonvolatile memory such as flash memoryand/or other suitable electronic data storage.

In operation, the GNSS receiver 202 may be operable to receive GNSSsignals from a plurality of visible GNSS satellites 120 a-120 c. TheGNSS receiver 202 may be operable to perform RF interference mitigationusing autoblanking and blank monitoring with watchguard. During the RFinterference mitigation process, the GNSS receiver 202 may be operableto assert autoblank signals using autoblanking. The GNSS receiver 202may be operable to monitor and determine the rate of the autoblanksignals. The GNSS receiver 202 may be operable to control the blankingof the received GNSS signals based on the determined rate of theautoblank signals. In instances when it is determined that the rate ofautoblank signals is too high, for example, the rate exceeds aparticular rate threshold, the GNSS receiver 202 may be operable todisable or stop the blanking of processing of received GNSS signals.

FIG. 3 is a block diagram illustrating an exemplary GNSS receiver thatis operable to provide RF interference mitigation using a blankingwatchguard, in accordance with an embodiment of the invention. Referringto FIG. 3, there is shown a GNSS receiver 300. The GNSS receiver 300 maycomprise a GNSS antenna 301, a GNSS front-end 302, a GNSS processor 304,a GNSS autoblanker 306, and a GNSS memory 308.

The GNSS antenna 301 may comprise suitable logic, circuitry, interfacesand/or code that may be operable to receive GNSS signals from aplurality of visible GNSS satellites such as the GNSS satellites 120 athrough 120 c. The GNSS antenna 301 may be operable to communicate thereceived GNSS signals to the GNSS front-end 302 for further processing.

The GNSS front-end 302 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to convert the received GNSSsignals to GNSS baseband signals, which may be suitable for furtherprocessing in the GNSS baseband processor 304 and in the GNSSautoblanker 306. The GNSS front-end 302 may be operable to detect andtrack GNSS signals.

The GNSS baseband processor 304 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to process GNSS basebandsignals from the GNSS front-end 302 to extract the information and databits conveyed in the received GNSS signals. The GNSS baseband processor304 may be operable to perform functions such as clock recovery, channelselection, demodulation, and/or decoding. The GNSS baseband processor304 may be operable to calculate navigation information such as aposition fix using the GNSS baseband signals from the GNSS front-end302. The GNSS baseband processor 304 may be operable to communicate thecalculated navigation information with the host processor 208 forvarious navigation applications such as E911 supported by the wirelesscommunication network 130. The GNSS baseband processor 304 may beoperable to process blanking signals from the GNSS autoblanker 306.Instances when the GNSS baseband processor 304 receives blanking signalsfrom the GNSS autoblanker 306, the GNSS baseband processor 304 may beoperable to stop the processing of received GNSS signals until theblanking signals stop.

The GNSS autoblanker 306 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to receive signals from theGNSS front-end 302 and perform RF interference mitigation usingautoblanking and blank monitoring with watchguard. During the RFinterference mitigation process, the GNSS autoblanker 306 may beoperable to assert autoblank signals using autoblanking. The GNSSautoblanker 306 may be operable to monitor and determine the rate of theautoblank signals and control the blanking of processing of receivedGNSS signals based on the rate of the autoblank signals. In instanceswhen it is determined that the rate of autoblank signals is too high,for example, the rate exceeds a particular rate threshold, the GNSSautoblanker 306 may be operable to disable or stop the blanking ofprocessing of received GNSS signals. The GNSS autoblanker 306 may beoperable to communicate blanking signals with the GNSS basebandprocessor 304 for further processing.

The GNSS memory 308 may comprise suitable logic, circuitry, interfacesand/or code that may enable storage of information such as executableinstructions and data that may be utilized by the GNSS basebandprocessor 304. The executable instructions may be utilized to calculatea position fix of the GNSS receiver 300 using GNSS measurements. Thedata may comprise the determined position fix of the GNSS receiver 300.The GNSS memory 308 may comprise RAM, ROM, low latency nonvolatilememory such as flash memory and/or other suitable electronic datastorage.

In operation, the GNSS antenna 301 may be operable to receive GNSSsignals for GNSS measurements. The GNSS front-end 302 may be operable toprocess the received GNSS signals and convert into GNSS basebandsignals. The converted GNSS baseband signals may be communicated withthe GNSS baseband processor 304 for GNSS baseband processing. Theprocessed GNSS baseband signals may be used to calculate a position fixof the GNSS receiver 300. The calculated position fix may be forward tothe host processor 210 for a navigation application. The GNSSautoblanker 306 may be operable to receive signals from the GNSSfront-end 302 and perform RF interference mitigation using autoblankingand blank monitoring with watchguard. During the RF interferencemitigation process, the GNSS autoblanker 306 may be operable to assertautoblank signals using autoblanking. The GNSS autoblanker 306 may beoperable to monitor and determine the rate of the autoblank signals. TheGNSS autoblanker 306 may be operable to control the blanking ofprocessing of the received GNSS signals based on the determined rate ofthe autoblank signals. In instances when it is determined that the rateof autoblank signals is too high, for example, the rate exceeds aparticular rate threshold, the GNSS autoblanker 306 may be operable todisable or stop the blanking of processing of received GNSS signals. TheGNSS autoblanker 306 may be operable to communicate blanking signalswith the GNSS baseband processor 304 for further processing. Ininstances when the GNSS baseband processor 304 receives the blankingsignals from the GNSS autoblanker 306, the GNSS baseband processor 304may be operable to stop the processing of received GNSS signals untilthe blanking signals stop.

FIG. 4 is a block diagram illustrating an exemplary GNSS autoblankerthat is operable to provide RF interference mitigation using a blankingwatchguard, in accordance with an embodiment of the invention. Referringto FIG. 4, there is shown a GNSS autoblanker 400. The GNSS autoblanker400 may comprise an autoblank detector 402, a blank monitor 404, a GNSSsignal 410, an autoblank signal 420, and a blank signal 430.

The autoblank detector 402 may comprise suitable logic, circuitry,interfaces and/or code that may be operable to receive a GNSS signal 410from, for example, an ADC converter in the GNSS front-end 302 describedwith respect to FIG. 3, detect the level of RF interference and assertan autoblank signal 420 during a RF interference mitigation process. Ifthe RF interference level is high, it may almost wipe out the GNSSsignal 410 to the point where it may be better not to process the GNSSsignal 410 (blank the GNSS signal processing) during that time using aRF interference mitigation method, such as, for example, theautoblanking method implemented by the autoblank detector 410. In anexemplary embodiment of the invention, the autoblank detector 402 may beoperable to establish consecutive time windows namely, for example,detector time windows for detecting the received GNSS signal 410 for RFinterference level. The autoblank detector 402 may establish a signallevel threshold as a reference for signal levels of received GNSSsignals 410. During the time within the detector time window, the numberof received GNSS signals 410 whose absolute signal levels exceed thesignal level threshold may be computed. The autoblank detector 402 mayestablish another threshold, namely, for example, a signal numberthreshold as a reference for above mentioned number of received GNSSsignals 410 whose absolute signal levels exceed the signal levelthreshold. The autoblank detector 402 may be operable to assert anautoblank signal 420 if the number of received GNSS signals 410 whoseabsolute signal levels exceed the signal level threshold exceeds thesignal number threshold.

The blank monitor 404 may comprise suitable logic, circuitry, interfacesand/or code that may be operable to receive an autoblank signal 420which may be asserted by the autoblank detector 402, monitor thereceived autoblank signals 420 and determine whether a blank signal 430may be generated or enabled based on the result of the monitoring ofreceived autoblank signals 420. An autoblank signal 420 may be assertedin instances when RF interference is detected. Some RF interference ison continuously such as in WCDMA transmissions (continuous jammer) andsome RF interference is on only for a burst of time such as in GSM orEDGE transmissions (burst jammer). In instances when the RF interferenceis a burst jammer, an autoblank signal 420 may be stopped as soon as theRF interference may go away and the RF interference mitigation processmay be stopped. On the other hand, in instances when the RF interferenceis a continuous jammer, an autoblank signal 420 may not be stopped for along time or may never be stopped during a RF interference mitigationprocess.

A blanking watchguard process may be implemented by the blank monitor404. In an exemplary embodiment of the invention, the blank monitor 404may be operable to establish consecutive time windows namely, forexample monitor time windows. The monitor time window may be much longerthan the detector time window used for autoblanking. A count may becomputed based on the number of total autoblank signals 420 receivedduring the time within the monitor time window. The blank monitor 404may be operable to establish a threshold namely, for example, a countthreshold as a reference for above mentioned count. In instances whenthe count exceeds the count threshold at the end of the monitor timewindow, the generation of a blank signal 430 may be disabled. Ininstances when the count does not exceed the count threshold at the endof the monitor time window, the generation of a blank signal 430 may beenabled. The blank signal 430, instead of the autoblank signal 420, maybe used to blank the processing of GNSS signals 410, for example, tostop the correlation process performed in the GNSS baseband processor304 described with respected to FIG. 3. The computed count may be apercentage of time within the monitor time window when one or more ofautoblank signals 420 are received and the count threshold may be aparticular percentage of time. The computed count may be the number oftotal autoblank signals 420 received during the time within the monitortime window and the count threshold may be a particular number ofautoblank signals 420. In an embodiment of the invention, the generationof a blank signal 430 may be disabled or enabled at a time prior to theend of the monitor time window, for example, at the middle of themonitor time window.

In operation, the autoblank detector 402 may be operable to receive GNSSsignals 410 during the RF interference mitigation process. During eachof the consecutive detector time windows, the number of received GNSSsignals 410 whose absolute signal levels exceed the signal levelthreshold may be computed. The autoblank detector 402 may be operable toassert an autoblank signal 420 if the number of received GNSS signals410 whose absolute signal levels exceed the signal level thresholdexceeds the signal number threshold. The blank monitor 404 may beoperable to receive autoblank signals 420 which may be asserted by theautoblank detector 402. During each of the consecutive monitor timewindows, a count, for example, the percentage of time within the monitortime window when one or more of autoblank signals 420 are received orthe number of total autoblank signals 420 received during the timewithin the monitor time window may be computed. The blank monitor 404may be operable to stop or disable the blank signals 430 in instanceswhen the count exceeds the count threshold at the end or, for example,at the middle of the monitor time window. The blank monitor 404 may beoperable to generate or enable the blank signals 430 in instances whenthe count does not exceed the count threshold at the end or at a timeprior to the end of the monitor time window, for example, at the middleof the monitor time window.

FIG. 5 is a flow diagram illustrating exemplary steps for RFinterference mitigation using autoblanking, in accordance with anembodiment of the invention. Referring to FIG. 5, the exemplary stepsmay start with step 510. In step 510, the autoblank detector 402 may beoperable to receive GNSS signals. In step 512, the autoblank detector402 may compute the number of received GNSS signals whose absolutesignal levels exceed the signal level threshold during the detector timewindow. In step 514, the end of the detector time window is checked. Ininstances when the end of the detector time window is reached, theexemplary steps may proceed to step 516. In step 516, in instances whenthe computed number is greater than the signal number threshold, theexemplary steps may proceed to step 518. In step 518, the autoblankdetector 402 may assert an autoblank signal and the exemplary steps mayproceed to step 510. In step 514, in instances when the end of thedetector time window is not reached, the exemplary steps may proceed tostep 510. In step 516, in instances when the computed number is lessthan or equal to the signal number threshold, the exemplary steps mayproceed to step 510.

FIG. 6 is a flow diagram illustrating exemplary steps for blankingwatchguard during RF interference mitigation process, in accordance withan embodiment of the invention. Referring to FIG. 6, the exemplary stepsmay start with step 610. In step 610, the blank monitor 404 may beoperable to receive autoblank signals 420 from the autoblank detector402. In step 612, the blank monitor 402 may compute a count based on thenumber of total autoblank signals 420 received during the monitor timewindow. In step 614, the end of the monitor time window is checked. Ininstances when the end of the monitor time window is reached, theexemplary steps may proceed to step 616. In step 616, in instances whenthe count is greater than the count threshold, the exemplary steps mayproceed to step 618. In step 618, the blank monitor 404 may be operableto disable the generation of a blank signal 430 and exemplary steps mayproceed to step 610. In step 614, in instances when the end of themonitor time window is not reached, the exemplary steps may proceed tostep 610. In step 616, in instances when the count is less than or equalto the count threshold, the exemplary steps may proceed to step 620. Instep 620, the blank monitor 404 may be operable to enable the generationof a blank signal and the exemplary steps may proceed to step 610.

In various embodiments of the invention, a global navigation satellitesystem (GNSS) enabled mobile device 200 may be operable to determine arate at which autoblank signals 420 are asserted. The autoblank signals420 may be asserted during the RF interference mitigation process usingautoblanking. The GNSS enabled mobile device 200 may be operable tocontrol the processing of received GNSS signals 410 based on thedetermined rate of asserted autoblank signals 420. In this regard, theGNSS enabled mobile device 200 may be operable to monitor the autoblanksignals 420 over time intervals corresponding to consecutive timewindows. The GNSS enabled mobile device 200 may be operable to determinea count of the autoblank signals 420 that are received during the timeinterval corresponding to the time window. The GNSS enabled mobiledevice 200 may be operable to compare the determined count to a countthreshold. In this regard, the count may be, for example, a percentageof time within the time window when the autoblank signals 420 arereceived, and the count threshold may be a particular percentage oftime. The count may also be, for example, a total number of theautoblank signals 420 received during the time window, and the countthreshold may be a particular number of the autoblank signals 420. TheGNSS enabled mobile device 200 may be operable to disable the generationof a blank signal 430 when the count is greater than the count thresholdat the end of the time window. The GNSS enabled mobile device 200 may beoperable to enable the generation of a blank signal 430 when the countis less than or equal to the count threshold at the end of the timewindow, and the blank signal 430 is used to blank the processing ofreceived GNSS signals 410. The GNSS enabled mobile device 200 may beoperable to disable the generation of a blank signal 430 when the countis greater than the count threshold at a time, for example, prior to theend of the time window. The GNSS enabled mobile device 200 may beoperable to enable the generation of a blank signal 430 when the countis less than or equal to the count threshold at a time, for example,prior to the end of the time window, and the blank signal 430 is used toblank the processing of the received GNSS signals 410.

Another embodiment of the invention may provide a machine and/orcomputer readable storage and/or medium, having stored thereon, amachine code and/or a computer program having at least one code sectionexecutable by a machine and/or a computer, thereby causing the machineand/or computer to perform the steps as described herein for RFinterference mitigation using a blanking watchguard.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system or in a distributed fashion where different elements arespread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

1-20. (canceled)
 21. A method for communication, the method comprising:in a global navigation satellite system (GNSS) enabled mobile device:asserting one of a plurality of autoblank signals when radio frequency(RF) interference is detected in received GNSS signals for a respectiveone of a plurality of consecutive first time windows; monitoring saidasserted autoblank signals over time intervals corresponding to arespective one of a plurality of consecutive second time windows;determining a rate at which said autoblank signals are asserted for saidrespective one of said plurality of said consecutive second time windowsbased on said monitoring; and determining whether to blank processing ofsaid received GNSS signals based on said determined rate.
 22. The methodaccording to claim 21, comprising asserting said autoblank signals basedon a number of said received GNSS signals whose absolute signal levelsexceed a signal level threshold for said respective one of saidplurality of consecutive first time windows.
 23. The method according toclaim 21, comprising determining a count of said autoblank signals thatare received during said time interval corresponding to said respectiveone of said plurality of consecutive second time windows.
 24. The methodaccording to claim 23, comprising comparing said determined count to acount threshold.
 25. The method according to claim 24, wherein saidcount comprises a percentage of time within said respective one of saidplurality of consecutive second time windows when said autoblank signalsare received, and said count threshold comprises a particular percentageof time.
 26. The method according to claim 24, wherein said countcomprises a total number of said autoblank signals received during saidrespective one of said plurality of consecutive second time windows, andsaid count threshold comprises a particular number of said autoblanksignals.
 27. The method according to claim 24, comprising disablingblanking of processing of said received GNSS signals when said count isgreater than said count threshold at an end of said respective one ofsaid plurality of consecutive second time windows.
 28. The methodaccording to claim 24, comprising enabling blanking of processing ofsaid received GNSS signals when said count is less than or equal to saidcount threshold at an end of said respective one of said plurality ofconsecutive second time windows.
 29. The method according to claim 24,comprising disabling blanking of processing of said received GNSSsignals when said count is greater than said count threshold at a timeprior to an end of said respective one of said plurality of consecutivesecond time windows.
 30. The method according to claim 24, comprisingenabling blanking of processing of said received GNSS signals when saidcount is less than or equal to said count threshold at a time prior toan end of said respective one of said plurality of consecutive secondtime windows.
 31. A system for communication, the system comprising: oneor more processors and/or circuits for use in a global navigationsatellite system (GNSS) enabled mobile device, said one or moreprocessors and/or circuits being operable to: assert one of a pluralityof autoblank signals when radio frequency (RF) interference is detectedin received GNSS signals for a respective one of a plurality ofconsecutive first time windows; monitor said asserted autoblank signalsover time intervals corresponding to a respective one of a plurality ofconsecutive second time windows; determine a rate at which saidautoblank signals are asserted for each of said respective one of saidplurality of consecutive second time windows based on said monitoring;and determine whether to blank processing of said received GNSS signalsbased on said determined rate.
 32. The system according to claim 31,wherein said one or more processors and/or circuits are operable toassert said autoblank signals based on a number of said received GNSSsignals whose absolute signal levels exceed a signal level threshold forsaid respective one of said plurality of consecutive first time windows.33. The system according to claim 31, wherein said one or moreprocessors and/or circuits are operable to determine a count of saidautoblank signals that are received during said time intervalcorresponding to said respective one of said plurality of consecutivesecond time windows.
 34. The system according to claim 33, wherein saidone or more processors and/or circuits are operable to compare saiddetermined count to a count threshold.
 35. The system according to claim34, wherein said count comprises a percentage of time within saidrespective one of said plurality of consecutive second time windows whensaid autoblank signals are received, and said count threshold comprisesa particular percentage of time.
 36. The system according to claim 34,wherein said count comprises a total number of said autoblank signalsreceived during said respective one of said plurality of consecutivesecond time windows, and said count threshold comprises a particularnumber of said autoblank signals.
 37. The system according to claim 34,wherein said one or more processors and/or circuits are operable todisable blanking of processing of said received GNSS signals when saidcount is greater than said count threshold at an end of said respectiveone of said plurality of consecutive second time windows.
 38. The systemaccording to claim 34, wherein said one or more processors and/orcircuits are operable to enable blanking of processing of said receivedGNSS signals when said count is less than or equal to said countthreshold at an end of said respective one of said plurality ofconsecutive second time windows.
 39. The system according to claim 34,wherein said one or more processors and/or circuits are operable todisable blanking of processing of said received GNSS signals when saidcount is greater than said count threshold at a time prior to an end ofsaid respective one of said plurality of consecutive second timewindows.
 40. The system according to claim 34, wherein said one or moreprocessors and/or circuits are operable to enable blanking of processingof said received GNSS signals when said count is less than or equal tosaid count threshold at a time prior to an end of said respective one ofsaid plurality of consecutive second time windows.